From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 07C5DC3A59E for ; Wed, 4 Sep 2019 06:06:13 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id CE6C223400 for ; Wed, 4 Sep 2019 06:06:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="jvpt9l+Z" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CE6C223400 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=vEV+bz/IVMqIZDbZj8geSrDBPNaGVHiLT5VKqdRR4Dc=; b=jvpt9l+ZR6itne cpTHjVSxR+vFcoyeGHyXYKYMDFgEsMHITSSPx/EyI/4TBf8YAdO+QBzC5oYIyzR+dEm5YNlujJFGw UwKopkJLFg3wJOjbj2CtuzmYv/jtkvSlNjmTr6OVMV8CGQ/1Z2QfQMdAvX97HD2xXrnWI/nEw/fv+ 2IVtQLV17DZRHp25sC+7c9L+s6Jii9Y0Y6jIwgAPk8O7yYE16R4Egd9xeIVoFpER2YjyAfNyRVmgN gwF1OSqAr3pJbz1VIubNyWzuUmhj+AB3tyVA0BLQqN+658gQHwo2QFOHF05qmgKhYuR4U08Jl5Vm5 n3bceotQ6lhBYtgDDv5A==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1i5OQi-0004jZ-I7; Wed, 04 Sep 2019 06:06:08 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.92 #3 (Red Hat Linux)) id 1i5OQf-0004j4-Pt for linux-nvme@lists.infradead.org; Wed, 04 Sep 2019 06:06:07 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 4D026227A8D; Wed, 4 Sep 2019 08:05:59 +0200 (CEST) Date: Wed, 4 Sep 2019 08:05:58 +0200 From: Christoph Hellwig To: Keith Busch Subject: Re: [PATCH] nvme-core: Fix subsystem instance mismatches Message-ID: <20190904060558.GA10849@lst.de> References: <20190831000139.7662-1-logang@deltatee.com> <20190831152910.GA29439@localhost.localdomain> <33af4d94-9f6d-9baa-01fa-0f75ccee263e@deltatee.com> <20190903164620.GA20847@localhost.localdomain> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190903164620.GA20847@localhost.localdomain> User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190903_230605_991745_4CFC7041 X-CRM114-Status: UNSURE ( 8.93 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Jens Axboe , Hannes Reinecke , Sagi Grimberg , "Martin K . Petersen" , linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, Keith Busch , Logan Gunthorpe , Christoph Hellwig Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Tue, Sep 03, 2019 at 10:46:20AM -0600, Keith Busch wrote: > Could we possibly make /dev/nvmeX be a subsystem handle without causing > trouble for anyone? This would essentially be the same thing as today > for non-CMIC controllers with a device-per-controller and only affects > the CMIC ones. A per-subsyste character device doesn't make sense, as a lot of admin command require a specific controller. If this really is an isue for people we'll just need to refcount the handle allocation. That is: - nvme_init_ctrl allocates a new nvme_instance or so object, which does the ida_simple_get. - we allocate a new subsystem that reuses the handle and grabs a reference in nvme_init_subsystem, then if we find an existing subsystem we drop that reference again. - last free of a ctrl or subsystem also drops a reference, with the final free releasing the ida _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme